Drying apparatus



April 23, 1946 F. J. BRoGLlE 2,398,880

DRYING APPARATUS 'Filed June 23, 1944 FWG. E.

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ATTORNEY f Permian 2.31.1946;

,OFFICE DRYING APPARATUS Francis J. Broglie, Mansneld, Ohio, assignor toWestinghouse Electric Corporation, East Pittsburgh, Pa.. a corporationof Pennsylvania Application June 23, 61944, Serial No. 541,797

Claims. (Cl. 34-45) My invention relates to apparatus for drying.

wet fabrics or the like and has for an object to provide improvedapparatus of this kind.

A further object of the invention is to substantially reduce the periodof time required for the drying of a batch of wet clothes in a drier ofthe domestic type having a heater for heating the fabrics and the airwithin the drier and a fan for translating air through the drier incontact with the fabrics. Y

It is a further object oi' the invention to initiate the circulation ofthe air within the drier only after the temperature of the air withinthe drying chamber has been elevated to a temperature optimum for dryingwhereby a substantial saving in heat is obtained.

A further object of the invention is to provide an automaticallycontrolled clothes drier of the domestic type wherein the drying cycleis initiated by the actuation of a single control device and wherein thedrying operation is terminated when the fabrics being treated are dry.

These and other objects are effected by my invention as will be apparentfrom the following description and claims taken in connection with theaccompanying drawing, forming a part of this application, in which:

Fig. 1 is a vertical sectional view of a domestic drier constructed andcontrolled in accordance with my invention; portions of the apparatusbeing shown in elevation;

Fig. 2 is a side elevation of the apparatus shown in Fig. 1 with aportion broken away to illustrate a door actuated switch;

Fig. 3 is a diagram ofthe electrical apparatus and the control mechanismtherefor; and

Fig. 4 illustrates a time-temperature curve for the apparatus disclosed.i

Clothes driers of the domestic type employed heretofore have included acasing, `a rotatable basket therein for tumbling the fabrics, a heaterfor heating the air in the casing and a fan for circulating air throughthe casing. Two methods have been employed for controlling the operationof the driers, one of which includes a simple on andoff" switch forstarting and stopping operation of the heater and the fan and atemperature limiting thermostat for preventing over-temperature in thedrier. The second control method is similar except that a time switch isemployed for the heater and fan which terminates operation of both aftera preselected period of operation. With both methods, the operator mustestimate .the period of drying and, as will be obvious, such estimationis dimcult as differentv kinds of .fabrics require different periods ofdrying. Accordingly, the fabrics may be underdried or the apparatus maybe operated longer than necessary. Since drying apparatus of this kindconsumes approximately 4500 watts, it will be apparent from aneconomical standpoint, that the drier should be operated no longer thanis absolutely necessary. i

In accordance with my invention, a single push button control device isemployed for energizing the main heater when initiating operation of thedrier. When the temperature within the drier casing has been elevated`to an efilcient drying temperature, such as. for example, 150 F., thecirculation oi' air through the casing is started by a thermostatarranged in the casing. During drying of the fabrics, the majority ofthe heat generated is converted to latent heat of vaporization so thatthe temperature rise within the cabinet at this time is small. As thefabrics become dried, less heat is converted to latent heat and more assensible heat so that the temperature of the air rises. When thetemperature of the air increases to a value of, for example, 190 F. atwhich time the fabrics are dry, the push button device isthermostatically moved to its oii position for deenergizing the heaters.The tumbling oi' the fabrics and the circulation of the air continue forpreventing wrinkling of the fabrics and for reducing the temperaturewithin the drier. Since operation of the heaters is manually initiated,they are not reenergized.

Operation of the basket and fan is automatically terminated when thetemperature in the casing is reduced to F. The entire drying cycle isautomatic after the push button has been operated for initiatingoperation. Since operation is terminated by temperature, the differentperiods of drying required by different loads are automaticallyeifected.

since the circulation of air is initiated only after the elcient dryingtemperature is attained in the casing, more eillcient operation isobtained and less heat discharged to the ambient atmosphere than wherecirculation of air accompanies the starting of the heaters. The dryingtime for a load of fabrics having a 9 lb. dry weight is reducedapproximately eight minutes when dried according to my invention,compared to the time required in driers of the type wherein circulationof air and heating of the same are simultaneously started. v

Reference will now be had to Figs. land 2 of ythe drawing. wherein Ihave shown my invention applied to a domestic type clothes drier, in

cluding a generally cylindrical casing' I0 partially covered by heatinsulating material I I and supported in any well ur'ierstood mannersuch as, for example, by means of brackets IIa within a. housing .I2. Aperforate container or basket I3 is rotatably supported within thecasing I0 and encloses the fabrics to be dried. As shown, the basket I3may be partially of wire mesh construction, a number of the wires beingshown at I4. The front end of the casing I is open, as shown at I5, toprovide access to a front opening I6 in the basket I3, said openingsproviding for the ingress and egress of the fabrics. The opening I isclosed by a suitable ldoor I1 which is hinged to the housing I2.

Heat is imparted to the air within the casing I0 by means of a pluralityof electric heaters I8 arranged within a cove I9 which may define aportion of the casing I0 and which is provided with air inlet openings2|. Preferably a reflector 22 is employed for reecting heat, radiatedbackwardly by the heaters I8, to the interior of the casing I0.

Air from the ambient atmosphere is translated through the casing I8 by ablower 23 which is driven by an electric motor 24, the latter alsoserving to rotate the basket I3 at its proper tumbling speed of, forexample, 50 R. P. M. The motor drives the backet I3 by means of a pulley25 carried by the motor shaft and belted, as shown at 26, to a sheave 21which is rotatable with the basket I3. The inlet of the blower 23 isconnected by means of a duct 28 to a bottom opening 29 formed in thecasing I0. Air discharged by the blower passes through an outlet opening3l formed in the housing I2 to the ambient atmosphere. Air from theambient atmosphere enters the housing I2 through a plurality of airinlet openings 32 which are arranged adjacent the air inlet openings 2|formed in the casing I0.

In accordance with my invention, the electrical heaters dlagrammaticallyshown at I8 in Fig. 3 are energized and deenergized under control of aswitch 35. Preferably, the heaters and the motor 24 are energized by athree-wire Edison circuit, the main or high voltage conductors of whichare indicated at L1 and Lz and the neutral by the reference character N.It will be assumed that the voltage across the conductors L1 and Lz'isapproximately 230 volts and that the voltage drop across eitherconductor L1 or La and the neutral N is 115 volts. As shown, oneterminal of the heaters I8 which are connected in series is connected tothe conductor L1 through the switch 35, while the opposite terminal ofthe heaters I8 is directly connected to the line conductor L2. A signallamp 36 is connected from the line conductor La to an intermediateterminal of the heat ers I8, as clearly shown in Fig. 3. At any and alltimes that the heaters I8 are energized, the lamp 36 will beilluminated.

The switch 35 denes an element of a control mechanism generallyindicated at 31 and carried in a convenient location, preferably on thefront of the housing I2, as shown in Fig. 1. The signal lamp 36 may bealso carried by the housing I2 adjacent the control mechanism 31. Themechanism 31 includes a handle or push button 38 for manually closingthe switch 35 and connected thereto by means of a pivoted lever 39, asclearly shown in Fig. 3. The movable end of the lever 39 is connected,preferably by a knife edge 4I, to one end of a pivoted horseshoe-spring42. The arrangement is such that the spring 42 will either bias thelever 38 to its switch-open position or to its switch-closed position,depending upon whether the lever 38 is above or below its dead centerposition, as is well understood. The switch 35 may be manually opened,if desired, by pulling up on the push button 38, but in normal operationthe switch 35 is opened by a thermostat, including an expansible bellows40 connected by means of a tube 40a to a heat responsive bulb 43arranged within the casing III, where it reflects the temperature of theair within the casing I0 and basket I3. The bellows 46, the tube 48a andthe bulb 43'are filled with uid which expands and contracts withincreases and decreases in the temperature of the iiuid within the bulb43.

Operation of the motor 24 is under control of a thermostat 44 supportedwithin the casing IU, as shown in Fig. 1, where it responds to thetemperature of the air within the casing I0 and the basket I3.Preferably, the thermostat 44 is of the bimetal disc type and includes asnap-over bimetal disc 45 carrying movable contacts 46, the latter beingengageable with stationary contacts 41 arranged in the neutral conductorN. Preferably, energization of the motor 24 is also controlled by adoor-operated switch 48 which is actuated to its closed position by thedoor I1 when the latter is closed. The switch 48 includes an arm 49engageable with the door in the closed position, as shown in Figs. 2 and3.

Operation In operating the drier, the damp fabrics as they come from thewringer or a centrifuge of a washing machine, are deposited in thebasket I3' through its access opening I6, after which the door I1 isclosed. The closing of the door closes the door-operated switch 48 andthereby conditions the circuit of the electric motor 24 forenergization. At this time, however, the motor 24 is not energized asthe thermostat 44 is in its open position. The operator then depressesthe push button 38 for closing the switch 35 and energizing the heatersI8 and the signal lamp 36. Since the motor 24 at this time isdeenergized, the basket I3 and fan 23 are inactive.

Heat is imparted to the air and to the drier structure within the casingI0 at this time, so that the temperature of the air is rapidly increasedas shown at A in the solid curve (Fif. 4). This temperature rise israpid due to the fact that there is no circulation of air through thecasing IU at this time. When the temperature of the air within thecasing III has been increased to an efcient drying temperature, such as,for example, 150 F., the thermostat 44 engages the contacts 46 and 41 sothat the motor 24 operates to rotate the basket I3 and to drive the fan23. The air entering the inlet openings 2I is rapidly heated as itpasses over the heaters I8 and the air within the casing I0 is heatedradiantly by i the heaters I8.v At this elevated drying temperature, theair has a high capacity for vaporizing and absorbing moisture from thefabrics, so that the majority of the heat generated at this time isconverted to latent heat of vaporization. Accordingly, the rise in thetemperature of the air during the drying period, which I have indicatedat B in Fig. 4, is relatively slow until such time that a substantialportion of the moisture has been vaporized and discharged to the ambientatmosphere. After about twenty-four minutes of operation, the rise intemperature of the air within the basket I3 becomes rapid due to the thesignal lamp 36 is deenergized, indicating that the drying operation hasbeen completed. Circulation of air and the tumbling of the fabricscontinues, however, until the temperature of the air has been depressedto approximately 150 F. at which time the thermostat 44 is actuated toits open position for deenergizing the motor 24. The decrease in airtemperature subsequent to the deenergization of the heaters and during`the continued operation of the fan 23 is shown at D on the solid curve(Fig. 4).

The operator mayv remove the fabrics at any time subsequent to thedeenergization of the heaters and the signal lamp 36. However, iftumbling and air circulation is permitted for a minute, the temperatureof the fabrics will be reduced so that they may be more comfortablyhandled. It will be understood, of course, that the door switch 48 willterminate rotation of the basket I3 as soon as the door I1 is opened inorder to prevent injury to the operator and facilitate the removal ofthe fabrics.

In the description of operation of the drier set forth heretofore, it isto be assumed that a `load of fabrics having a dry weight of 9 pounds isdried and that these fabrics contain 9 pounds of water when admitted tothe drier. A further assumption is that 4400 watt heaters are employedand that approximately 150 cubic feet of air per minute is circulated.

The curve shown in broken lines indicates operation of the drier in themanner employed heretofore, wherein circulation of air and energizationof the heaters are simultaneously initiated. It will be apparent thatthe heating-up portion of the cycle shown at E, to the eflicient dryingtemperature of 150 F., is much slower than Where the circulation isdelayed, as described, and that the entire drying cycle is lengthened byabout eight minutes. The undulating portion of the curve shown at Frepresents the temperature uctuation when a cycling type overtemperaturethermostat is employed for the control of the heaters.

It will be apparent from the foregoing description that I have providedan improved drier for fabrics wherein the drying time for a given loadis substantially reduced. The drier is automatically controlled andcompensation for different loads is obtained so that no estimate of thedural tion of the drying period is required on the part of the operator.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptibleof various changes and modifications without departing from the spiritthereof, and I desire, therefore, that only such limitations shall beplaced thereupon as are specifically set forth in the appended claims.

What I claim is:

1. In apparatus for drying fabrics or the like, the combination of aperforate container for receiving the fabrics to be dried and movableabout an axis, means for actuating the container about its axis fortumbling the fabrics therein, means for translating air through thecontainer in contact with the` fabrics, means for (heating the air inthe container, a thermostat responsive to the temperature of the air inthe container for controlling operation of said heating means andeffective in response to a predetermined high temperature of the air forterminating substantially, the heating effect of said heating means,`and a second thermostat controlling operation of the air translatingmeans in response to the temperaure of the air in the container, saidsecond thermostat responding to a temperature of the air lower than saidfirst-mentioned high temperature for initiating operation of the airtranslating means.

2. In apparatus for drying fabrics or the like, the combination of aperforate container for receiving the fabrics to be dried and movableabout an axis, means for actuating the container about its axis fortumbling the fabrics therein, means for translating air through thecontainer in contact with the fabrics, means for heating the air in thecontainer, manually operated means for initiating operation of theheating means, means responsive to a predetermined high temperature ofthe air in said container for terminating operation of the heatingmeans, and thermostatic means responsive to the temperature of the airin the container for controlling operation of the air translating means;said thermostatic means being effective to start and stop operation ofthe air translating means in response to temperatures lower than saidpredetermined high temperature.

3. In apparatus for drying fabrics or the like, the combination of aperforate container for receiving the fabrics to be dried and movableabout an axis, Vmeans for actuating the container about its axis wherebythe fabrics are `tumbled therein, means for translating air through thecontainer ii contact with the fabrics, a heater for imparting heat tothe air in the container, manually operated means for initiatingoperation of the heater, means responsive to a predetermined hightemperature of the air within the container for terminating operation ofthe heater and thermen.

static means responsive to the temperaturev of the air in the containerfor controlling operation of the container actuating means and the airtranslating means, said thermostatic means being effective in responseto temperatures lower than said predetermined high temperature forinitiating'and terminating operation of the container actuating meansand the air translating means.

4. In a drier for fabrics or the like including a casing, a rotatableperforate basket arranged within the casing for receiving wet fabrics tobe dried, means for rotating the basket, means for translating airthrough the basket in contact with the fabrics, means for heating theair within the basket, a thermostat for controlling operation of theheating means and manually actuated to a first position for initiatingoperation of the heating means, said thermostat being moved to a secondposition in response to a predetermined high temperature of the airwithin the casing for terminating operation of the heating means, and

, a second thermostat responding to predetermined temperatures of theair within the casing lower than the first-mentioned predetermined hightemperature of the air, for starting and stopping operation' of thebasket rotating means and said air translating means.

5. In apparatus for drying wet fabrics or the like, the combination of arotatableperforate container for receiving the fabrics to be dried,means including an electric motor for rotating the container whereby thefabrics are tumbled therein, air translating means driven by saidelectric .motor for circulating air through the container in contactwith the fabrics, an electric heater for imparting heat to the air inthe container, a switch for controlling energization of the electricheater and manually moved to 'a closed position for initiating operationof the heater, means responsive/ to a predetermined high temperature ofthe air within the container for open..

means including an electric motor for rotatingthe container whereby thefabrics are tumbled therein, air translating means driven by saidelectric motor for circulating air through the container in contact withthe fabrics, an electric heater for imparting heat to the air in thecontainer, a switch for controlling energization of the electric heaterand manually movable to closed and open positions for respectivelyenergizing and deenergizing said heater, means responsive to apredetermined high temperature of the air within the container foropening said switch, and thermostatic means responsive to thetemperature of the air in the container for controlling the operation ofsaid motor; said thermostatic means being effective to initiate andterminate operation of the motor in response to temperatures lowerthansaid predetermined high temperature.

7. In apparatus for drying wet fabrics or the like, the combination of acasing structure having an access opening therein and a door for closingthe opening, a perforate container for the fabrics rotatably supportedwithin the casing structure, an electric heater disposed within thecasing structure for heating, radiantly, the fabrics and the air withinthe casing structure, a motor for actuating the container, a fan drivenby the motor for translating air through the casing structure in contactwith the fabrics, a switch manually actuated to its closed position forenergizing said heater, means responsive to a predetermined hightemperature of the air within the casing structure for opening saidswitch, and a thermostat responsive to the temperature of the air withinthe casing structure for controlling operation of said motor, saidthermostat being effective to start and stop the motor in response totemperatures of the air in the casing structure which are lower thansaid predetermined high temperature.

8. The combination as clauned in claim 'l including a second switchactuated by said door and opened and closed therewith for controllingoperation of the motor.

9. In apparatus for drying fabrics or` the like, the combination of aperforate container for receiving the fabrics to be dried and movableabout an axis, means for actuating the container about its axis fortumbling the fabrics therein, means for translating air through thecontainer in contact with the fabrics, means for heating the air in thecontainer, a thermostat responsive to the temperature of the air in thecontainer for controlling operation of said heating means and effectivein response 4to a predetermined high temperature of the air forterminating substantially, the heating effect of said heating means, anda second thermostat controlling operation of the air translating meansand the container actuating means in response to a temperature of theair within the container lower than said predetermined high temperatureto which the first-mentioned thermostat responds.

l0. In apparatus for drying fabrics or the like, the combination of aperforate container for receiving the fabrics to be dried and movableabout an axis, means for actuating the container about its axis for,tumbling the fabrics therein, means for translating air through thecontainer in contact with the fabrics, means for heating the air in thecontainer, a thermostat responsive to the temperature of the air in thecontainer for controlling operation of said heating means and effectivein response to a predetermined high temperature of the air forterminating substantially, the heating effect of said heating means, anda second thermostat controlling operation of the air translating meansand the container actuating means in response to the temperature of theair in the container, said second thermostat responding to a temperatureof the air lower than said first-mentioned high temperature forterminating operation of the air translating means and containeractuating means.

FRANCIS J. BROGLIE.

